Question

two waves of amplitude 4A and 2A have a phase difference of Pi between them. the resultant intensity will be

Answer 1

Answer: $I = 2A$

Explanation:

Given that,

Two waves of amplitude is

$A_{1} = 4A$

$A_{2} = 2A$

Phase difference $\phi = \pi$

We know that .

The resultant intensity

$I =\sqrt(A_{1}^{2}+A_{2}^{2}+2A_{1}A_{2}cos\phi)$

$I = \sqrt(16A^{2}+4A^{2}+2\times4A\times2A\times cos\pi$

$I = \sqrt(16A^{2} +4A^{2} - 16A^{2}$

$I = 2A$

Hence, the resultant intensity will be 2A.